Hollow screen structure ceramic-metal composite electrode

Abstract

The utility model relates to a kind of hollow screen structure ceramic-metal composite electrode, it includes screen, stainless steel framework and stainless steel air inlet pipe;Multiple grooves are provided on the outer cylindrical surface of screen along the circumferential direction interval, and metal electrode piece is respectively embedded in each groove;The lower end column wall of screen is uniformly distributed with screen air hole;Stainless steel air inlet pipe is uniformly distributed with air pipe air hole on the pipe wall inside screen;Stainless steel framework includes multiple stainless steel metal rods along the circumferential direction interval, and one end of each stainless steel metal rod is respectively connected and fixed with corresponding metal electrode piece, and the other end of each stainless steel metal rod is respectively connected and fixed with the pipe wall of stainless steel air inlet pipe;The edge of the stainless steel framework is connected and fixed with conducting rod.The electrode system of the utility model can realize the efficient in-situ conversion of CO2 in high-temperature molten salt environment, and the morphology consistency and crystallinity of the product carbon nanotube are significantly better than traditional process, providing a controllable and stable technical path for large-scale preparation of high-performance carbon materials.

Description

Technical Field

[0001] This utility model relates to the field of carbon nanotube preparation technology using carbon dioxide, and specifically to a hollow sieve structure ceramic-metal composite electrode. Background Technology

[0002] To address global climate change and synergistically advance economic and social development, energy security, and the "dual carbon" goal, numerous novel carbon dioxide capture, storage, and utilization (CCUS) technologies have been extensively developed, including high-temperature molten salt CO2 capture and electroreduction methods. This technology can not only reduce CO2 emissions from traditional fossil fuel combustion on a large scale and efficiently, but also convert them into commercially valuable carbon nanotubes and oxygen. As the core component for the CO2 conversion reaction, the electrode's performance and structure play a crucial role in the efficiency and effectiveness of the entire system. An excellent electrode should possess good gas diffusion, mass transfer efficiency, electrocatalytic activity, and mechanical stability, among other factors. However, previous electrode designs have several limitations. For example, the effective contact area between traditional electrodes and the electrolyte is small, resulting in low ion transport efficiency and limited reaction rates; the electrode's structural stability is insufficient, making it prone to deformation or corrosion during long-term operation, thus reducing electrolysis efficiency and equipment lifespan.

[0003] The prior patent CN202311286684 describes a method for preparing carbon nanotubes by electrolyzing carbon dioxide in a non-lithium calcium-based molten salt. A binary mixture of sodium carbonate and potassium carbonate is used as the molten salt electrolyte, with additives such as calcium carbonate, strontium carbonate, or barium carbonate added. An inert anode and a catalytically active metal cathode are employed, and electrolysis is carried out at 700℃-1000℃. The cathode product is then treated with acid washing, centrifugation, and drying to obtain carbon nanotubes. However, the experimental setup suffers from a problem where the gas inlet pipe and cathode are separated, resulting in significant CO2 loss and delayed electrolysis, leading to low electrolysis efficiency and allowing for further improvement in product morphology. Summary of the Invention

[0004] The purpose of this invention is to overcome the shortcomings of the prior art and provide a hollow screen structure ceramic-metal composite electrode.

[0005] To achieve the above objectives, the present invention adopts the following technical solution:

[0006] A hollow sieve structure ceramic-metal composite electrode is used for the synchronous in-situ electrolysis of CO2 to prepare carbon nanotubes. The composite electrode includes a sieve, a stainless steel skeleton, and a stainless steel air inlet pipe.

[0007] The screen is made of alumina ceramic and has a hollow cylindrical structure that runs through the top and bottom. The outer cylindrical surface of the screen has multiple grooves spaced along the circumference, and each groove is embedded with a metal electrode sheet.

[0008] The lower end column wall of the screen is evenly distributed with screen air holes;

[0009] The lower end of the stainless steel air inlet pipe extends into the inside of the screen, and the stainless steel air inlet pipe has air pipe holes evenly distributed on the pipe wall inside the screen.

[0010] The stainless steel frame includes multiple stainless steel metal rods spaced apart along the circumference. One end of each stainless steel metal rod is connected and fixed to a corresponding metal electrode plate, and the other end of each stainless steel metal rod is connected and fixed to the wall of the stainless steel air intake pipe. The stainless steel air intake pipe forms a conductive path with each stainless steel metal rod and each metal electrode plate.

[0011] A conductive rod is fixed to the edge of the stainless steel frame, and the conductive rod is connected to the negative terminal of the power supply.

[0012] Furthermore, the outer diameter of the screen is 3cm and the height is 8cm; the width of the groove is 5mm, the depth is 3mm and the height is 8cm; the width of the metal electrode sheet is 5mm, the height is 8mm and the thickness is 1mm.

[0013] Furthermore, the pore size of the screen is 300 μm.

[0014] Furthermore, the diameter of the stainless steel air inlet pipe is 5mm.

[0015] Furthermore, the diameter of the tracheal pore is 1 mm, and the distance between adjacent tracheal pores is 5 mm.

[0016] Furthermore, the screen is made by molding alumina powder and sintering at high temperature.

[0017] By adopting the above technical solution, the beneficial effects of this utility model are as follows:

[0018] This invention constructs a hollow porous sieve-metal composite electrode specifically for in-situ carbon dioxide electrolysis. Through the synergistic design of the porous network and hollow structure, this electrode integrates the entire process of CO2 gas absorption, electrolytic reduction, and product production into a single system. The porous sieve configuration of the electrode directly serves as a carrier for CO2 diffusion and reaction. Gas naturally permeates into the electrolyte through uniformly distributed pores, forming a high-density gas-liquid-solid three-phase reaction interface with the molten salt electrolyte. The grooved structure on the sieve surface, with its height difference from the metal electrode sheet, restricts the directional growth of carbon nanotubes to a predetermined metal region, preventing carbon material from covering the pores. The microenvironmental regulation function of the sieve surface ensures precise growth of carbon nanotubes at catalytic sites, avoiding pore blockage. This electrode system achieves highly efficient in-situ CO2 conversion in a high-temperature molten salt environment. The morphological consistency and crystallinity of the produced carbon nanotubes are significantly better than those of traditional processes, providing a controllable and stable technical path for the large-scale preparation of high-performance carbon materials. Attached Figure Description

[0019] The present invention will be further described in detail below with reference to the accompanying drawings and specific embodiments:

[0020] Figure 1 This is a perspective view of the overall structure of this utility model;

[0021] Figure 2 This is a top view of the overall structure of this utility model;

[0022] Figure 3 This is a detailed diagram of the air holes in the screen. Detailed Implementation

[0023] like Figure 1-3 As shown, this utility model discloses a hollow sieve structure ceramic-metal composite electrode for the simultaneous in-situ electrolysis of CO2 to prepare carbon nanotubes. The composite electrode includes a sieve 3, a stainless steel frame 5, and a stainless steel air inlet pipe 2.

[0024] Screen 3 is made of high-purity alumina ceramic, and is manufactured by molding alumina powder and sintering at high temperature. Screen 3 has an outer diameter of 3cm and a height of 8cm.

[0025] The outer cylindrical surface of the screen 3 is provided with multiple grooves spaced along the circumference. Each groove is fitted with a metal electrode sheet 4. The groove is 5mm wide, 3mm deep, and 8cm high. The metal electrode sheet 4 is 5mm wide, 8mm high, and 1mm thick.

[0026] The lower end column wall of the screen 3 is evenly distributed with screen pores 7; the pore diameter of the screen pores 7 is 300μm. The screen pores 7 are densely distributed within a height of 1.5cm from the bottom of the screen 3, and the porosity of this part of the screen pores 7 is controlled at 60-80%.

[0027] The lower end of the stainless steel air inlet pipe 2 extends into the inside of the screen 3. The stainless steel air inlet pipe 2 has air pipe holes 6 evenly distributed on the inner wall of the screen 3. The diameter of the stainless steel air inlet pipe 2 is 5mm. The diameter of the air pipe holes 6 is 1mm, and the distance between adjacent air pipe holes 6 is 5mm.

[0028] The stainless steel frame 5 includes multiple stainless steel metal rods (1.25 mm in diameter) spaced apart along the circumference. One end of each stainless steel metal rod is connected and fixed to the corresponding metal electrode plate 4, and the other end of each stainless steel metal rod is connected and fixed to the wall of the stainless steel air intake pipe 2. The stainless steel air intake pipe 2 forms a conductive path with each stainless steel metal rod and each metal electrode plate 4.

[0029] A conductive rod 1 with a diameter of 1mm is fixed to the edge of the stainless steel frame 5, and the conductive rod 1 is connected to the negative terminal of the power supply.

[0030] The embedding of the metal electrode sheet 4 is a crucial step in achieving electrode conductivity. First, the metal electrode sheet 4 undergoes pretreatment including mechanical grinding, ultrasonic cleaning, acetone degreasing, and dilute sulfuric acid removal of the oxide film to effectively enhance its stability in the high-temperature molten salt environment. The pretreated metal electrode sheet 4 is then directly embedded into multiple grooves, ensuring a tight bond between the metal electrode sheet 4 and the screen 3, forming good electrical contact. Next, the metal electrode sheets 4 in each groove are connected by a stainless steel frame 5, forming a complete conductive path. The stainless steel frame must have sufficient strength to support the screen 3 and ensure the dimensional accuracy of the hollow portion, facilitating gas flow and distribution.

[0031] The hollow screen 3-structure ceramic-metal composite electrode of this invention requires quality control and performance testing. The electrode appearance is inspected to ensure there are no obvious defects, damage, or deformation, and the electrode dimensions are accurately measured to ensure they meet design requirements. After pretreatment including mechanical grinding, ultrasonic washing, acetone degreasing, and dilute sulfuric acid removal of the oxide film, the electrode's electrochemical performance, including conductivity, electrochemical stability, and carbon dioxide reduction current efficiency, is tested in a simulated electrolysis environment to evaluate whether the electrode performance meets expectations.

[0032] Through the above steps, a hollow sieve 3-structure ceramic-metal composite electrode with high carbon dioxide reduction capability can be fabricated, providing key technical support for the electrochemical conversion of carbon dioxide to prepare carbon nanomaterials.

[0033] This invention uses high-purity alumina ceramic as the substrate for the screen, with a porous structure to ensure efficient diffusion and transport of CO2 gas. The outer cylindrical surface of the screen is designed with a concave-convex structure, with metal electrode sheets embedded in the grooves, ultimately forming multiple uniformly distributed composite metal electrode sheets. This electrode not only possesses excellent conductivity to meet the current transport requirements during electrolysis, but also exhibits good corrosion resistance, enabling stable operation in high-temperature molten salt environments. During electrolysis, CO2 can enter the electrolyte through the pores of the screen, achieving efficient CO2 absorption and reduction reactions. The ingenious design of the micro-convex structure on the outer cylindrical surface of the screen allows carbon nanotubes to preferentially grow in the metal electrode sheet area, while the raised areas form a physical barrier, effectively preventing products from covering the screen pores and ensuring continuous CO2 diffusion. This unique structural design significantly increases the contact area between the composite electrode and CO2, promotes CO2 diffusion on the composite electrode surface, improves CO2 mass transfer efficiency, provides abundant active sites for electrochemical reactions, and thus enhances the overall performance of the electrode.

[0034] Compared with traditional flat plate electrodes, this invention not only solves the problems of local overheating and reaction runaway caused by uneven current distribution, but also achieves in-situ coupling of CO2 adsorption, diffusion, and electrolysis by integrating the gas inlet pipe with the electrode. In traditional processes, the CO2 input point is separated from the cathode, and the current is concentrated at the electrode edge or specific points, which easily leads to unstable reaction interface and uneven product morphology. The invented ceramic-based hollow sieve overcomes this bottleneck through the following mechanism: the porous structure creates a through diffusion channel for CO2 from the gas inlet to the reaction interface, allowing it to directly enter the electrolyte through the sieve pores and fully contact the molten salt electrolyte; at the same time, the high distribution of micropores on the sieve significantly enhances the CO2 dispersion ability, while the uniformly distributed metal electrode sheets provide stable active sites for the electrolysis reaction. Crucially, the concave-convex interval structure on the outer cylindrical surface of the sieve precisely restricts the directional growth of carbon nanotubes in the metal region, while the continuous introduction of CO2 avoids clogging of the pores, forming a dynamic cycle of "adsorption-electrolysis-product generation". This invention significantly enhances CO2 mass transfer and reaction kinetics by integrating the gas-liquid-solid three-phase reaction interface in situ. It achieves an integrated process from gas input to carbon nanotube generation in a high-temperature molten salt environment. The product's microstructure consistency and crystal quality meet industrial controllable standards, providing an innovative solution for efficient and low-energy CO2 resource utilization technology.

[0035] The specific embodiments of this utility model have been described above. However, those skilled in the art should understand that this is only an example. Those skilled in the art can make various changes or modifications to this embodiment without departing from the principle and essence of this utility model, but all such changes and modifications fall within the protection scope of this utility model.

Claims

1. A hollow sieve structure ceramic-metal composite electrode for the simultaneous in-situ electrolysis of CO2 to prepare carbon nanotubes, characterized in that: The composite electrode includes a screen, a stainless steel frame, and a stainless steel air inlet pipe. The screen is made of alumina ceramic and has a hollow cylindrical structure that runs through the top and bottom. The outer cylindrical surface of the screen has multiple grooves spaced along the circumference, and each groove is embedded with a metal electrode sheet. The lower end column wall of the screen is evenly distributed with screen air holes; The lower end of the stainless steel air inlet pipe extends into the inside of the screen, and the stainless steel air inlet pipe has air pipe holes evenly distributed on the pipe wall inside the screen. The stainless steel frame includes multiple stainless steel metal rods spaced apart along the circumference. One end of each stainless steel metal rod is connected and fixed to a corresponding metal electrode plate, and the other end of each stainless steel metal rod is connected and fixed to the wall of the stainless steel air intake pipe. The stainless steel air intake pipe forms a conductive path with each stainless steel metal rod and each metal electrode plate. A conductive rod is fixed to the edge of the stainless steel frame, and the conductive rod is connected to the negative terminal of the power supply.

2. The hollow screen-structured ceramic-metal composite electrode according to claim 1, characterized in that: The screen has an outer diameter of 3cm and a height of 8cm; the groove has a width of 5mm, a depth of 3mm, and a height of 8cm; the metal electrode has a width of 5mm, a height of 8mm, and a thickness of 1mm.

3. The hollow screen-structured ceramic-metal composite electrode according to claim 2, characterized in that: The pore size of the screen is 300 μm.

4. The hollow screen-structured ceramic-metal composite electrode according to claim 2, characterized in that: The diameter of the stainless steel air inlet pipe is 5mm.

5. The hollow screen-structured ceramic-metal composite electrode according to claim 2, characterized in that: The diameter of the tracheal pore is 1 mm, and the distance between adjacent tracheal pores is 5 mm.

6. The hollow screen-structured ceramic-metal composite electrode according to claim 1, characterized in that: The screen is made by molding alumina powder and sintering at high temperature.

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